Abstract: A scanning head (12) for a surface measuring machine has a probe tip (30), which is supported by a probe tip support lever (18) so that it can be deflected perpendicularly to the reference surface (82). Incorporated between the probe tip (30) and a rigid section of the probe tip support lever (18) is a force sensor (34), whereof the output signal serves as an actual value of a control circuit (56 to 60), which controls a magnetic servo motor (44, 46), which exerts a variable additional force, to be added to the force of a tension spring (42), on the probe tip support lever (18), the whole so that the contact pressure of the probe tip (30) is kept constant irrespective of the surface contour.

Abstract: An optical thickness measuring instrument for transparent work-piece, in particular glass plates and transparent films, consists of a scanning head (10) with a servo-controlled measuring lens (24), a mirror (12) arranged perpendicularly to the axis of the latter and means (66 to 72) for positioning the work-piece (64) in parallel above the mirror (12). The servo control adjusts the measuring lens (24) so that a measuring light source (34) is focussed on the surface of the mirror. For this purpose, the measuring lens (24) must be adjusted by the associated servo drive (18, 20) depending on the thickness of the work-piece (64). The electrically measured (40) adjustment displacement of the measuring lens (24) is a measurement of the thickness of the work-piece (64). (FIG. 1).

Abstract: A regulating circuit for the servo drive for the mobile precision optics of an equipment for high-precision measuring of micro-contours of a work-piece surface contains a position transmitter (40) which ascertains the actual position of the precision optics to correct disturbances caused by vibration and shaking. This is part of an internal loop comprising a proportional-derivative controller (68) and an integral controller (70). An external loop which predetermines the reference input for the internal loop formed by these elements contains an integral controller (74) which receives a signal from a detector (82) which corresponds to the spacing of the just measured point on the test surface from the focal point of the precision optics. The local reflection behaviour of the test surface is measured (84) and used for correcting the gradient of the control characteristics (86).

Abstract: An optical scanning head (10) for measuring the surface of a work-piece (12) contains an integrated microscope. For this purpose, a deflecting mirror (38) located in the wall of the housing (14) of the scanning head is constructed as a dielectric mirror, which is impermeable for measured light, on the other hand is permeable for observation light and is also machined to optical quality on its rear side. Seated behind this deflecting mirror (38) are a tube lens (70) and an ocular lens (72), which together with the objective (24) of the scanning head (10) form a microscope.

Abstract: An apparatus for the highly accurate measurement of measuring surfaces (14) has a lens (68) pre-tensioned by spring members (84, 86), which lens is connected to a magnetic adjusting sleeve (74). The latter cooperates with an annular coil (140) surrounding it. A light source (60) directs a narrow light beam (62) towards the measuring surface (14). The beam reflected by the latter is deflected by a combination prism (90) and split into two partial beams, which reach photoelectric transducers (116, 118). The output signal thereof serves for adjusting the supply current for the annular coil (140). Provided behind the lens (68) is a glass plate (78) which is mirrored with the exception of a central circular region (82), so that light beams reflected by the measuring surface with a considerable inclination with respect to the axis of the apparatus are thrown back again onto the measuring surface and are supplied to the detection system along the axis of the apparatus.